1. Field of the Invention
The present invention relates generally to an attachment for an electromechanical device for use with anastomosing, stapling, and resecting surgical tools, and more specifically to a stapling and resecting device which can be attached to and serve as an extension of an electromechanical device driver, and most specifically to the expanding parallel jaws and the mechanisms thereof.
2. Description of the Prior Art
Upon identification of cancerous and other anomalous tissue in the gastrointestinal tract, surgical intervention is often prescribed. The field of cancer surgery, and more specifically, the surgical procedure by which a section of the gastrointestinal tract which includes cancerous tissue is resected, includes a number of uniquely designed instruments. In combination with a description of the present instrumentation and their functions, a description of the state of the art in this surgical procedure shall also be provided.
The first question which must be answered when determining how to treat gastrointestinal tract cancer relates to the specific location of the cancerous tissue. This is very important insofar as the instruments which are provided in the present art have limitations relating to how far they may be inserted into the gastrointestinal tract. If the cancerous tissue is too far up or down the gastrointestinal tract, then the standard instrumentation provided is unusable, thus requiring special accommodations. These accommodations generally increase the risk of contamination of the surrounding tissues with bowel contents, increase the length of the surgery and the corresponding need for anesthesia, and eliminate the benefits of precise anastomosing and stapling which comes from utilizing a mechanized device.
More specifically, in the event that the cancerous tissue is located at a position in the colon which is accessible by the present instrumentation, the patient""s abdomen is initially opened to expose the bowel. The surgeon then cuts the tube of the colon on either side of the cancerous tissue, while simultaneously stapling closed the two open ends of the bowel (a distal end which is directed toward the anus, and the proximal end which is closest to the lower intestine). This temporary closure is performed in order to minimize contamination. The linear cutter and stapling instrument which is used in the prior art is provided in a perspective view in FIG. 1.
More particularly, this temporary closure is achieved when the colon is placed between the scissoring elements at the tip of the linear cutter and stapling instrument. By squeezing the trigger in the handle of the device, the surgeon causes the scissoring elements to come together. A second trigger (or a secondary action of the same trigger) is then actuated to drive a series of staples and a cutting blade through the clamped end of the colon, thereby closing and transecting the ends.
After the sealing of the two exposed distal and proximal ends, the surgeon creates a small opening in the proximal end of the bowel and inserts the removable anvil portion of an anastomosing and stapling instrument. This step, as well as those of the remainder of the surgical procedure, are related to the functioning of this surgical instrument which is provided in a perspective view in FIG. 2. More particularly, the surgeon begins by taking the instrument and manually turning the dial at the base of the handle which causes the anvil head at the opposite end to advance forward. The surgeon continues to turn the dial until the anvil head advances to its most extreme extended position. This manual turning requires nearly thirty full rotations. Once fully extended, the anvil head of the instrument is decoupled therefrom and is inserted into the exposed proximal end such that the coupling post extends outwardly therethrough. As described above, this proximal end is then stapled closed. The extending shaft of the anastomosing and stapling instrument is then inserted and advanced into the lower colon, transanally, until the coupling stem thereof extends through the stapled distal end. The surgeon then joins the coupling ends of the anvil and shaft together and begins to manually rotate the dial in the handle again, this time bringing the anvil head closer to the tip of the shaft.
Once the anvil head and shaft are brought close together, after the surgeon has manually rotated the dial another thirty times, a grip-style trigger in the handle is manually actuated. This actuation causes a circular blade to advance axially out from the tip of the shaft, and into contact with the opposing face of the anvil. The blade cuts through the stapled-closed ends of the proximal and distal ends of the colon, thereby also cutting a new pair of ends of the proximal and distal portions of the colon. The tissue which has been severed is held in an interior volume at the end of the shaft.
In lock step with the cutting the freshly opened ends are joined together by a series of staples which are advanced through holes in the perimeter of the tip of the shaft (being pressed against and closed by the opposing face of the anvil). The coupled shaft and anvil are then withdrawn from the patient.
More particularly with respect to the structural features of the linear stapling instrument of the prior art which is provided in FIG. 1, the device comprises a pistol grip-styled structure having an elongate shaft and distal portion. The distal portion includes a pair of scissors-styled gripping elements which clamp the open ends of the colon closed. In fact only one of the two scissors-styled gripping elements, the anvil portion, moves (pivots) relative to overall structure; the other remains fixed. The actuation of this scissoring means (the pivoting of the anvil portion) is controlled by means of a grip trigger maintained in the handle. A number of different means have been disclosed for holding the tips of the scissoring arms closed, including snaps, clips, collars, et al.
In addition to the scissoring means, the distal portion also includes a stapling mechanism. The non-moving element of the scissoring mechanism includes a staple cartridge receiving region and a mechanism for driving the staples up through the clamped end of the colon, against the anvil portion, thereby sealing the previously opened end. The scissoring elements may be integrally formed with the shaft, or may be detachable such that various scissoring and stapling elements may be interchangeable.
More particularly with respect to the structural features of the anastomosing and stapling instrument of the prior art which is provided in FIG. 2, the device comprises an anvil portion, a staple, blade and reservoir portion, a shaft portion, and a handle portion. The anvil portion, which is selectively removable from the tip of the shaft, is bullet shaped, having a blunt nosed top portion, a flat cutting support surface on the bottom, and a coupling post extending axially from the bottom surface.
The staple, blade, and reservoir portion (SBR portion) of the instrument is provided at the distal end of the instrument, and includes a selectively advanceable and retractable coupling stem for selectively receiving thereon the anvil portion. This action of the coupling stem is provided by a screw threaded shaft and worming mechanism mounted in the handle (described more fully below). The SBR portion is cylindrical in shape, forming a housing which has a hollow interior. It is this hollow interior which forms the reservoir. The blade is similarly cylindrical, and seats in the inside of the housing, against the inner wall thereof. The blade is selectively advanceable axially outward from the housing, in accordance with actuation of a trigger mechanism of the handle (again, described more fully below). On the axially outward facing surface of the cylindrical wall of the housing are a series of staple ports, through which the staples of the device are discharged. The same actuation which drives the blade forward similarly drives a series of staple drivers forward within the cylindrical walls. More accurately, the staple driver is a cylindrical component which has a series of protuberances on the axial end thereof, the protuberances being positioned in accordance with the distribution of staples and holes. The staples, prior to being discharged, are mounted in the holes; and they are advanced through the holes by the action of the staple driver and the protuberances thereof.
The shaft portion of the instrument is a simple rigid extended structure which is intended as a sheath for a pair of elongate rods. The first rod is coupled to the worming mechanism introduced above, and described more fully below with respect to the handle portion, and is the means by which the anvil portion and the coupling stem of the SBR portion are selectively advanced and retracted. The second rod is coupled to the trigger of the handle at one end (also introduced above, and described more fully below) and to the blade and staple driver at the other end. The sheath protects the patient and the instrument when it is advanced into the colon transanally. The nature of the actuation mechanisms however, requires that the shaft be rigid. This rigidity limits the length of the shaft; and combination, i.e. the length and rigidity of the instrument, these features limit the sections of the colon which may be treated using this device.
The handle of this instrument of the prior art comprises a pistol grip styled structure having a turning dial at the butt (i.e. the end opposing the junction of the shaft portion which the handle) and a finger actuated trigger. The trigger includes a safety mechanism which physically prevents actuation unless moved out of the interference position. The turning dial is actionably coupled to a worming mechanism which is used to advance the first rod of the shaft portion (thereby advancing the coupling stem and the anvil). The trigger functions as a basic lever to push the second rod forward within the shaft, thereby advancing the blade and staple driver.
As with many such devices of the prior art, all of these devices are considered fully disposable, and are, in fact, thrown away after a single use. They are complicated devices, having multiple moving parts, requiring substantial structural integrity and, therefore, expense in manufacturing. The fact that they are used only once, and no part can be used again render the use of such devices expensive and wasteful of resources.
In addition to this failure, as can be readily observed from the preceding descriptions, the prior art devices suffer from numerous other limitations which would be desirable to overcome. These include the rigid and limited length shaft of the devices, as well as the requirement that the surgeon manually actuate all of the features and functions.
Therefore, it is a principal object of the present invention to provide an instrument for resecting and stapling gastrointestinal tissue during colon surgery, which reduces the waste of resources by permitting use as an attachment to an electromechanical device driver.
It is further an object of the present invention to provide an instrument assembly which reduces the requirements for the surgeon to manually actuate different components and mechanisms.
It is further an object of the present invention to provide a resecting and stapling mechanism that can be integrated with other electromechanical devices into an attachment for use with an electromechanical device driver.
Other objects of the present invention shall be recognized in accordance with the description thereof provided hereinbelow, and in the Detailed Description of the Preferred Embodiment in conjunction with the remaining Figures.
The preceding objects of the invention are provided by virtue of an electromechanical resecting and stapling attachment which is coupleable to and remotely actuateable by an electromechanical device driver. In particular, the attachment includes a pair of linearly spreading jaws for clamping the selected section of gastrointestinal tissue therebetween, said jaws expanding and closing in a parallel disposition. More particularly, the linear clamping mechanism of the attachment is used to first clamp the section of colon, and then to hold the colon in place as a blade extends along a track in the lower jaw of the clamping attachment to cut the section of bowel, and then drives a series of staples through the two opened ends so that the contents of the bowel are not permitted to empty into the surrounding region of the abdomen. This attachment, and others necessary to perform the remainder of the surgery, is coupled to an electromechanical driver which is described more fully hereinbelow.
More particularly, with respect to the electromechanical driver, the driver has a handle and a flexible drive shaft. The handle has a pistol grip-styled design, having a pair of finger triggers which are independently coupled to separate motors which each turn separate flexible drive shafts (described more fully, hereinbelow). The motors are each dual direction motors, and are coupled to a manual drive switch mounted to the top of the handle, by which the user can selectively alter the turning direction of each motor. This dual direction capacity may be most simply achieved by selecting motors which turn in a direction corresponding to the direction of current, and actuation of the drive switches alters the direction of the current accordingly. In this example, the power source supplying the motors must be a direct current source, such as a battery pack (and most desirably, a rechargeable battery pack). In the event that the device should be useable with an alternating current, either a transformer can be included, or a more sophisticated intermediate gearing assembly may be provided. In conjunction with the present description, the embodiments of the present invention which will be described utilize a rechargeable battery pack providing a direct current.
In addition to the motor components, the handle further includes several other features, including: (1) a remote status indicator; (2) a shaft steering means; and (3) at least one additional electrical supply. First, the remote status indicator may comprise an LCD (or similar read out device) by which the user may gain knowledge fo the position of components (for example whether a clamping element is in the proper position prior to the driving of the staples). Second, the handle also includes a manually actuateable steering means, for example, a joystick or track ball, for directing the movement of the flexible shaft (by means of guidewaves implanted in the shaft portion described more fully hereinbelow). Finally, the handle may include an additional electrical power supply and an on off switch for selectively supplying electrical power to the attachments.
More particularly, with respect to the flexible shaft, the shaft comprises a tubular sheath, preferably formed of a simple elastomeric material which is tissue compatible and which is sterilizable (i.e. is sufficiently rugged to withstand an autoclave). Various lengths of this shaft may be provided in conjunction with the present invention. In this case, the flexible shaft and the handle portions should be separable. If separable, the interface between the proximal end of the shaft and the distal end of the handle should include a coupling means for the drive components. Specifically regarding the drive components of the shaft, within the elastomeric sheath are a pair of smaller fixed tubes which each contain a flexible drive shaft which is capable of rotating within the tube. The flexible drive shaft, itself, simply must be capable of translating a torque from the motor in the handle to the distal end of the shaft, while still being flexible enough to be bent, angled, curved, etc. as the surgeon deems necessary to xe2x80x9csnakexe2x80x9d through the bowel of the patient. For example, the drive shafts may comprise a woven steel fiber cable. It shall be recognized that other drive shafts may be suitable for this purpose. In order for the distal end of the drive shaft to couple with an attachment, such as the clamping and stapling device of the present invention (as described more fully below), however, the distal tips of the drive shafts must have a conformation which permits the continued translation of torque. For example, the distal tips of the drive shafts may be hexagonal, thereby fitting into a hexagonal recess in the coupling interface of the attachment. As suggested above, in conjunction with the manually actuateable steering means mounted to the handle, the sheath further includes at least two guidewires which are flexible, but are coupled to the inner surface of the sheath near the distal end thereof. The guidewires may be axially translated relative to one another by actuation of the steering means, which action causes the sheath to bend and curve accordingly. Also, as suggested above, in conjunction with the LCD indicator of the handle, the shaft further contains an electrical lead for coupling to the attachments. This electrical lead channels a signal from the attachment to the handle for indicating the status of the attachment (for example, whether a clamping function is holding). Similarly, a second electrical lead may be provided to supply power to separate aspects of the attachment if so required (for example, as will be described more fully with respect to linear resecting and stapling attachment, the use of selectively engageable electromagnetic seal for ensuring continued clamping through the stapling process may be provided and require power selectively provided from the handle""s power supply).
More particularly, with respect to the linear resecting, clamping, and stapling attachment which is the specific subject of this invention, the attachment is fitted with two drive extensions, which in operation function as extensions of the flexible drive shafts of the electromechanical driver. That is, when the attachment is mated to the electromechanical driver, the drive extensions are in mechanical communication with the flexible drive shafts such that the activation of the drive shaft motors activates the drive extensions within the linear clamping, cutting and stapling attachment The first drive extension enables the parallel spreading and closing of the jaws of the device, which form a linear clamping mechanism, while the second drive extension enables a cutting and stapling mechanism. More particularly, the linear clamping mechanism comprises a separating jaw system whereby an upper jaw is raised to permit the bowel tissue to be placed therebetween, and subsequently the jaws are closed to meet to effect a clamping. In a first embodiment, the first drive extension engages a pair of threaded vertical shafts which raise or lower the upper jaw depending on the turning direction of the corresponding motor in the electromechanical driver. In a second embodiment, the first drive extension includes only a single angled gearing mechanism mounted at the end of the horizontally rotating shaft (which is coupled to one of the turning shafts of the electromagnetic driver). This gearing mechanism causes the vertically rotation of a threaded shaft on which the upper jaw is separately munted. In both embodiments, when the jaws are closed, a pair of sensor electrodes disposed on the jaws come into contact and thereby complete a sensor circuit which alerts the surgeon that it is safe or appropriate to activate the resecting and stapling mechanism and/or automatically activates the resecting and stapling mechanism.
In each of these embodiments, the second driver causes a blade to slide along a track in the lower jaw, which blade cuts the bowel, briefly leaving two open ends. Nearly simultaneous with the cutting, a stapling mechanism drives a series of staples upwardly through opening in the lower jaw, toward the upper jaw, through the open ends, thereby closing the bowel segments. This stapling action happens nearly simultaneous with the cutting in part because the blade is contiguous with a stapling mechanism of the present invention.
This stapling mechanism begins with a replaceable tray of open staples which is set within the lower jaw, the tray having two rows of staples separated along the long axis of the jaw so that the blade may track between the rows. The opposing upper jaw face includes a set of corresponding staple guides, such that when the linear clamping mechanism is in a closed position, the open staples immediately oppose the corresponding staple guides. This mechanism comprises a wedge pushing system whereby once the linear clamping mechanism is in a closed position, the blade and a wedge ride along together in a channel below the tray of open staples, and the staples are pushed up toward the staple guides, through the bowel. More particularly, as the wedge moves through the channel a sloping surface of the wedge pushes the open staples against the corresponding staple guides, thereby closing the staples. After the staples have been closed, the wedge is pulled back through the channel. It is the first drive mechanism which lifts the jaws apart in parallel; and it is the second drive mechanism which pushes or pulls the wedge and blade mechanism through the channel. The direction of the first and second mechanisms is related solely to the remote operation of the driver, and the corresponding turning direction of the shafts, of the electromechanical driver.